Do not insert SamplingDotCsr when there is no blas

theano/sparse/opt.py

@@ -1646,6 +1646,9 @@ sampling_dot_csr = SamplingDotCSR()
 # register a specialization to replace SamplingDot -> SamplingDotCsr
 @gof.local_optimizer([sparse.sampling_dot])
 def local_sampling_dot_csr(node):
+    if not theano.config.blas.ldflags:
+        # The C implementation of SamplingDotCsr relies on BLAS routines
+        return
     if node.op == sparse.sampling_dot:
         x, y, p = node.inputs
         if p.type.format == 'csr':
@@ -1656,6 +1659,7 @@ def local_sampling_dot_csr(node):
 
             return [sparse.CSR(z_data, z_ind, z_ptr, p_shape)]
     return False
+
 sparse.register_specialize(local_sampling_dot_csr,
                            'cxx_only',
                            name='local_sampling_dot_csr')

theano/sparse/tests/test_opt.py

@@ -130,5 +130,11 @@ def test_local_sampling_dot_csr():
                             sparse.sampling_dot(*inputs),
                             mode=mode)
 
-        assert not any(isinstance(node.op, sparse.SamplingDot) for node
+        if theano.config.blas.ldflags:
+            assert not any(isinstance(node.op, sparse.SamplingDot) for node
+                       in f.maker.fgraph.toposort())
+        else:
+            # SamplingDotCSR's C implementation needs blas, so it should not
+            # be inserted
+            assert not any(isinstance(node.op, sparse.opt.SamplingDotCSR) for node
                        in f.maker.fgraph.toposort())